Automatic heat-treating machine



June 5, 1951 Filed Aug. 28, 1945 D. M. STRAUCHEN ET AL AUTOMATIC HEAT'TREATING MACHINE 6 Sheets-Sheet 1 fly. 4.

INVENTOR-b June 5, 1951 D. M. STRAUCHEN ET AL 2,555,517

AUTOMATIC HEAT-TREATING MACHINE Filed Aug. 28, 1945 e Sheets-Sheet 2 8.9 W l l INVEN TORS 04 v10 1% Sumac/I54 fia ran 640w My. wa /it ATYVRA'IY June 5, 1951 D. STRAUCHEN EI'AL 2,555,517

AUTOMATIC HEAT-TREATING umcam:

Filed Aug. 28, 1945 6 Sheets-Sheet 3 I] ,2 fi I X I N V EN TORS 041w M .5714 aanw #14 raw 644" By om/ Arroxm June 1951 D. M. STRAUCHEN ETAL 2,555,517

AUTOMATIC HEATTREATING MACHINE Filed Aug. 28, 1945 6 Sheets-Sheet 4 INVENTORS 12,1 141-04 waft Irma/all Huron 6 W. m: y

June ,1951 1 D. M. STRAUCHEN mu. 2,555,517

AUTOMATIC HEAT-TREATING MACHINE Filed Aug. 28, 1945 e Sheets-Sheet 5 Arraxyn I June 5, 1951 D. M. STRAUCHEN ETAL' 2,555,517

AUTOMATIC HEAT-TREATING MACHINE Filed Aug. 28, 1945 6 Sheets-Sheet 6 //a/ m 1% e9 ll -u m INVENTORS DA Jmaucmw ATTORN! Y Patented June 5, 1951 AUTOMATIC HEAT-TREATING MACHINE David M. Strauchen and Milton Garvin, Cincinnati, Ohio, assignors to The Cincinnati Milling Machine 00., Cincinnati, Ohio, a corporation of Ohio Application August 28, 1945, Serial No. 613,090

7 Claims.

This invention relates to heat treating apparatus and more particularly to improvements directed toward producing an apparatus or machine for heat treating purposes which is entirely automatic in operation. One of the reasons for heat treating metallic articles is for prevention against wear, and since this can be accomplished by simply hardening a thin layer of the outside material of the article to be treated a method known as flame hardening is utilized because of its efficiency in that an intense heating effect can be produced at the necessary surface areas without heating the entire article. From a metallurgical standpoint, however, these heating operations are very critical, there being a correct temperature and time of quench for each of the various metals and alloys, departure from which results in an inferior product.

It has been found that even duplicate parts composed of the same material may take slightly different lengths of time to arrive at the same quenching heat. Thus, a number of variables, some predictable and some not, enter into such a heat treating operation. Heat treating machines of the past have required. skilled operators and, even then, exact results have not been obtained. Take, for instance, in the measuring of heat, some use a time control on the assumption that similar articles will heat in exactly the same time-which has been found to be untrue-while others use an electric eye apparatus for cutting off the heat, but such apparatus is not sensitive throughout the heating cycle and variations in temperature are not noted.

This invention obviates these difficulties, and one of the objects of thisinvention is to provide a complete automatic machine for heat treating purposes in which the variable factors are automatically compensated for in such a manner that not only is each Work piece heated to exactly the same temperature regardless of the time it takes to heat it, but the quench is applied at the proper interval of time after heating, and all in such a quick and efficient manner that very high production rates can be obtained and the machine may be operated by unskilled operators whose only duty is to load and start the machine.

Another object of this invention is to provide a machine for the purposes described which is compact, durable, efficient in operation, and economical to build.

A further object of this invention is to provide a new and improved automatic control mechanism for a machine of the character described which may be preset to the desired quenching temperature and which will automatically, upon attainment of that temperature by the work, shut down the machine, extinguish the heat, quench the work and place the machine in readiness to receive a new work piece.

A still further object of this invention is to provide an improved automatic heat treating machine which is especially suitable for heat treating the surfaces of circular work pieces such as gears, cams, and the like, which are ordinarily difficult to uniformly heat by providing automatic and sequential controls for starting rotation of the work, applying the heat, and when the work has reached the desired temperature, shutting off the heat, stopping the work rotation, ejecting and quenching the work.

Another object of this invention is to provide a machine of the character described which is automatic in operation and suitable to be placed in a high production manufacturing or assembly line for heat treating mechanical parts which are used in large quantities in highly mechanized production plants, such as .for heating gears in a supply line for gear box assemblies in automobile manufacturing plants.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure 1 is a front elevation of a machine embodying the principles of this invention.

Figure 2 is a side view, as viewed from the left, of the machine shown in Figure l with certain parts broken away to show the Work supporting and ejecting mechanism.

Figure 3 is an enlarged fragmentary portion of one of the torch supporting brackets.

Figure 4. is a detail section on the line 44 of Figure 3.

Figure 5 is a section on the line 5-5 ofFigure 2.

Figure 5 is a view on the line 66 of Figure 2.

Figure 7 is an enlarged end View of one of the burners.

Figure 8 is a section on the line 88 of Figure 3.

Figure 9 is a modified form of the machine shown in Figure 1.

Figure 10 is a section on the line lii-l 8 of Figure 9.

Figure 11 is a diagram of the control circuit for the machine.

Figure 12 is an elevational view of a modified form of torchhead.

Figure 13 is a sectional View as viewed on the line l3-l3 of Figure 12.

Figure 14 is a diagrammatic View ofa control circuit for sequential operation of the gas valves.

One embodiment of a machineexeinplifying the principles of this invention is shown in Figures 1 and 2 in which the reference numeral It indicates the bed of the machine, and from the backof this bed there upstands a column portion II.

This machine is designed for handling rotary work and to that end the machine is provided with a work supporting spindle 52 which is supported in bearings t3, mounted in a housing It which is supported on the rear side of the column wall 15. The spindle projects through the column wall and some distance in front of it so that the heating operation of the work supported on the end of the spindle will be spaced some distance from the wall to prevent heating thereof. For further protection, the front of the wall is provided with a layer of asbestos material It to prevent the. passage of heat through the wall to the instrumentalities located behind the wall.

The spindle It. is provided with a removable arbor l! sothat diiferent size arbors may be substituted therefor, whereby an arbor may be chosen that has a diameter equal to the. diameter of the hole. in. the work piece to be treated to the end that a. good sliding fit. may be obtained. The arbor is provided with a. key to fit the keyway in the work piece and thereby form a driving means for rotation of the work. It has been found that if a good sliding fit between the work and arbor is obtained that it is not necessary to provide any retainer for the work on the end of the arbor such as a nut or the like to hold the. work on during rotation, and this simplifies the operation of the machine because the operator simply has to place. the work on the arbor and an automatic ejecting means can slide the work off at any time.

In the cases of work pieces that have no central bore but have a projecting stud the removable arbor may be made in the form of a. chuck for receiving the stud.

The spindle i2 is provided with a sprocket wheel l8 through which it is driven by a variable speed motor l9 connected thereto through a sprocket wheel 2!] and driving chain 2|. The motor is preferably of the gear reduction type and the drive from the pulley iii! to the pulley Iii is also a reducing drive so that the work piece represented by the reference numeral 22 may be rotated at a relatively slow speed around 80 to 190 revolutions per minute. The speed of work revolution is varied in accordance with the diameter ofthe'work insuch a-manner as to give a constant peripheral speed past'the heating burners, and it has beenfound that a peripheral speed of 100 R. P. M. gives the most satisfactory rate of heating. In order to effect variations in the ultimate speed of the work, a rheostat or other speed controlling unit 23 is placed in the control circuit for the motor as more particularly shown in Figure 4.

The work is heated by rotating the same in the center of a heating zone developed by placing a series of burners or tips around the periphery of the work, the number and position of which will vary in accordance with the size of the work and the configuration of its outer surface. For illustration purposes there has been shown two torches '24 and 25 which are supported on opposite sides of the work, and each torch is provided with. a series of tips or burners 25. The face 2'! of the torch head is provided with two or three rows of threaded holes in which the burners or tips are attached as shown in Figure 7. It is usually not necessary to use all of these holes and so the remainder are closed by threaded plugs as indicated at 28.

The tips or burners 2B are made of different length as shown in Figure 1 of the drawings so that the end of. each tip is substantially the same distance from the periphery of the work, and this makes it possible to place the highest temperature zone of the flame in proper relation to the surface to be heated. It will be noted that the burners all extend in parallel relation rather than in radial relationwith respect to the center of rotation of the work and the advantage of this is that in cases where the work has indentations therein that. the flame from the burner on one side of the center of rotation will obtain good contact with one wall of the indentation and the flame from the. burners on the lower side of center will obtain a good contact with the other wall of the indentation, thereby obtaining a more uniform manner of heating action.

For the purposes of adjustment and set-up and to take care of variations in the size of work and the manner in which it is to be heated, the torchheads are supported on the top of the bed 5-24 for variable adjustment. The adjustable support for each head is the same. For instance the torchhead 24 which is rectangular. in cross section is mounted in a rectangular slot 29 of an angularly adjustable bracket 30. The torchhead is secured in the slot by a, pair of screws 3| as shown in Figure. 8. The bracket has a circular flange 32 which is rectangular in cross section and fits into a rectangular slot 33 formed in the upper end of an upright or standard 34 as shown in Figure 3. The flange 32 is provided with a circular slot 35 and through this slot passes a clamping screw 36 which is threaded at one end 3'! into the upright 34 for frictionally clamping the flange in the upright in whatever angular position it is desired to place the torchhead. The periphery of the flange 32 is graduated at 32a for cooperation with a fixed reference mark 32b on the upright 34 so that a given setting of the torchhead may be reproduced for a given style of work piece and also that the opposite torchhead may be similarly adjusted. It is often necessary, however, to give the opposite torchheads an opposite angle of adjustment, as for instance when treating helical gears, because the teeth on one side of the gear are, of course, opposite in angle to the teeth on the other side; therefore, the torchheads have to be angularly adjusted in accordance therewith.

The uprights 34 are secured to the end of blocks 38 by a screw 39 which passes through a slotted hole 4-8 in the member 34 to permit vertical adjustment thereof. The blocks 38 are fastened by screws Q! to longitudinally adjustable slides 42 which slide on top of T--slotted plates 43 secured to the bed lil. T-headed bolts M, as shown in Figure 4, mounted in the T-slotted member 43 pass through the plate 42 for the purpose of clamping the same. The plate 52 is provided with graduations 45 which cooperate with a zero mark 46. to determine the location of the parts and for purposes of reproducing the position.

Similarly, the upright 34 has graduations 4i which cooperate with a zero mark .8 to give location of the parts and permit reproducing the setting. It will now be apparent that the. torchheads may be adjusted toward and from one another and may also be vertically adjusted as well as angularly adjusted.

The torches are provided with a mixture of oxygen and acetylene gas through a supply pipe 41 which is connected by means of an elbow 48 to the rear of the torch head. As shown in Figure 11, the supply pipe 41' is connected to a mixing chamber 49 and this chamber has two inlets 50 and 5|, the inlet 55 supplying the oxygen and the inlet 5| supplying the acetylene. Individual control valve knobs 52 and 53 determine the mix ture of gases in the chamber 49 and the mixed gas then fiows through the pipe 4'i' to the burners. The inlet 59 is connected by a pipe 54 to a shutoff valve 55 and the inlet 5| is connected by a pipe 56 to a shut-off valve 5?. It will be noted from Figure 11 that duplicate control systems are pro vided for each burner, and duplicate shut-off valves 55 for the oxygen, and duplicate shut-off valves 51 for the acetylene are provided for each burner.

The shut-off valves 55 have branch connections 58 to a main source of oxygen supply represented by the numeral 59. The shut-off valves 51 are connected by branch connections 55 to a main source of acetylene supply represented by the numeral 6|. The shut-off valves 55 and 5's are connected by pins 52 to a solenoid operated lever 53 which is pin-connected at 54 to a bracket 55, formed integral with the valve block 65. Springs 61 interposed between the top of the valve block and the lever 53 act to normally hold the supply valves closed. It will thus be seen that after the mixture for each torchhead has been determined by the valve adjusters 52 and 53 that in normal operation of the machine the shut-off valves are automatically opened to provide a supply of gas and when the operation is completed the supply of gas is shut oil.

After the gear has been heated to the correct temperature it is automatically removed from the work supporting spindle by an ejector mechanism. This mechanism comprises a plunger 58 which is slidably mounted in an electric solenoid l9 supported on the rear side of the front wall [5 of the column. A spring H is interposed between a shoulder 12 formed on the plunger and a supporting block 13 for normally holding th plunger in a retracted position. As shown Figure l a plate 14 is attached by a bolt 15 to the front end 69 of the plunger 58 and in this plate are threadedly secured a pair of ejector fingers l5. These fingers are made of relatively soft metal so that they may be readily bent to suit the shape of the work, thereby eliminating the necessity for providing lateral adjustment of the fingers in the supporting plate. It will now be obvious that when the solenoid 19 is electrically energized that the plunger will move forward and push the work piece off of the spindle. The work piece is given a sufficient kick that it will hit a deflecting plate I! and fall into the quenching oil in the quenching tank i8 located in the bed Ill of the machine.

In the embodiment of the machine shown in Figures 1 and 2 the quenching tank 18 is made as a separate unit which is adapted to be pulled forward out of the bed of the machine for removal of the work which has been treated. In order to permit easy removal of the work the tank has pair of rollers 19 secured to each side, and the bed of the machine is provided with angle iron tracks upon which these rollers move. As shown in Figure 2, the rollers 19 are secured to the rear of the tank to support the weight at the rack end, and the front end of the tank is provided with a roller caster 81 to support the weight at the front end of the tank.

The tank is provided with a wire basket 82 which may be lifted out of the tank by hand or by an overhead crane, depending upon the weight of the work. To facilitate removal of the tank the front wall 83 of the tank is provided with hand holes 84 for gripping the handle portions 85.

The temperature of the work is determined directly and accurately by radiation, and this is accomplished by supporting an electric thermopile, represented generally by the reference numeral 86 in Figure 5, which is supported in the upper end of a viewing tube 81. This tube is supported in spaced relation to an outer tube 88 which is pivotally connected on opposite sides at 89 to a bifurcated arm 99. The arm 59 has an axially slidable connection with a bifurcated block 9! which is slidably mounted on an upright standard 52 and adapted to be clamped thereto by a screw passing through the bifurcated portion of the member 9!. Standard 92 is mounted on the top of the column I I. By means of these various connections the viewing tube may be adjustably positioned in suitable spaced relation with the peripheray of the work to collect the heat radiation from a definite portion of the surface of the work and direct it on the thermopile. In order to prevent the iiarnes from the burning gas from overlapping on the top of the work and thereby interfering with the true radiation of the heat from the work a compressed air supply pipe 94 is threadedly connected at 95 to the side of the tube 8'! as shown in Figure 5 to provide a gentle downward flow of air through the end of the tube to keep the flame away from the top surface of the work at the point where the heat measure-- ment is made.

As shown in Figure 11 the thermopile is electrically connected by a pair of wires 96 and 91 for operation and movement of a movable indicator 2% of a temperature control instrument 99 of a known commercial type which has a presettable indicator I50. It is sufiicient to say at this time that when the movable indicator 98 reaches a position in juxtaposition to the presettable indicator I80 that an electrical control switch It]! is opened within the instrument to cause automatic shutdown of the machine and ejection of the work. In other words, the instrument 99 has a normally closed switch ml and this switch is connected in series between a power main I92 with a starting switch 553 and a relay IM to a power main I05.

The manner in which the various operating devices, such as the work driver, the gas control valve, the ejector, the gas igniter and the temperature control mechanism are coupled together to obtain automatic operation of the machine. will now be explained in connection with Figure 11. The control circuit shown in this figure is so designed that a complete automatic cycle may be effected by merely pushing the cycle control start button I95, or alternatively the various op erating devices ma be controlled separately as for set-up purposes.

The automatic cycle will first be explained and in this cycle the operator loads a work piece on the spindle and presses the start button I03 after which the entire cycle of the machine is automatically controlled so that the operator has nothing tov do until. it istime to lo'adanother work piece on the machine. The automatic sequence of events. in an automatic cycle is as follows: rotation of the work, turning on the gas, and igniting the gas. The work is thus rotating in the heating zone and the temperature of the work begins to rise causing movement of the movable temperature indicator 98. When the temperature as recorded by this indicator reaches the temperature as indicated by the presettable indicator I the switch I0! opens causing the gas to be shut off, thereby extinguishing the heating flames, the work stops rotating, and the ejector forces the work piece off of the spindle causing it to be quenched in the quenching tank.

Referring to Figure 11, the operator first closes the main switch I0 8 to connect current to the power lines I02 and M35 of the circuit shown. The

automatic cycle of operation is started by closing the cycle control start switch I03 which energizes the latching in relay I 04, thereby causing contacts I04a to complete a latching-in circuit through normally closed stop button I0! around the starting switch E03 so that a circuit is now completed through relay I04, closed contacts I04c, stop button I01, and normally closed instrument switch IOI to power line I02. For automatic cycle of operation, the operator has set the selector switch I08 on contact button I09 so that upon operation of the starting push button I03 the automatic cycle control relay III] is also energized.

The operation of relay H0 closes contacts Iii, thereby completing a circuit through line II2, branch line H3 to starter I I4 for the work driv ing motor I9. This starter relay closes contacts 8 I 5 to energize coil I Hi and thereby close the circuit through lines II! and M8 to the motor I9. Line H8 is connected by branch line II9 to the power main I05 and the line It? is connected through the speed regulator 23 and branch line I to power main 02. The result is that the motor 59 starts the rotation of the work.

Operation of the automatic cycle control relay IIO also closes contacts I2I to complete a circuit from power main I05 through line i22 to the gas control relay I23. Operation Of this relay closes contacts I 24 to complete a circuit from power main I02 to line I25 which is connected in parallel to the gas valve control solenoids i20 and 22. The other side of these solenoids is connected in parallel by line I28 to power main I05. The result of this operation is that the gas valves are open whereby the torches are supplied with gas. The closing of the latching-in relay I04, closes contacts I24 which completes a circuit from power main I05 through line I25, normally closed stop button E25, line l2'i, and normally closed stop button I28 to the junction point I29. When the relay I23 closed, it closed a pair of contacts I30 completing a circuit from junction point I20 to relay I23, and also closed a pair of contacts I35, closing a circuit from power main I05 to timer relay I32. The relay I23 also closed a pair of contacts 533 in series with a. pair of normally closed contacts I34 of timer relay I32, in a circuit between the secondary I 31 of a transformer I 38 and a primary I39 of a spark coil I40.

The normally closed contacts I34 are controlled by the timer relay I32 which has a timed opening and an instantaneous closing. Therefore, when the contacts I33 closed, a circuit was momentarily established between the transformer I30 and spark coil until the contacts I34 are opened by the timer relay I32. Thereafter the circuit remains open until the machine stops.

8 1 At that time the relay I23v releases first to open contacts I3I and I33 and thereby release timer relay I32 which subsequently closes contacts I34 without establishing a new circuit connection but it does condition the circuit for the next cycle of operation.

The primary I4: of the transformer I38 is permanently connected. to the lines II9 and I20 which lead to the power mains I05 and I02 respectively. Therefore, closing the intermediate circuit energizes thespark coil. I40 and its secondary I42 whereby a spark is created across the spark gap I43 which is located adjacent each of the burners to ignite the gas. The result of the initial operation of the circuit is that the work is being rotated, the gas has been turned on and ignited, and the work begins to heat up.

The thermopile is sensitive to the rising temperature of the work, causing movement of the temperature indicator 98. When the temperature of the work reaches the temperature shown by the presettable indicator I00, the instrument switch I M opens. This breaks the circuit to both of the relays I04 and H0. The deenergization of the automatic cycle relay ill] opens contacts III, thereby breaking the circuit to the work driving motor control relay H4, thereby breaking the circuit to the motor whereby the Work stops rotating. Also, the opening of contacts I24 associated with relay 104 and contacts 525 associated with relay IIO breaks the circuit to relay I23 and timer relay I32. The deenergization of relay I23 opens contacts I24 whereby the solenoids I25 and IZ'I are deenergized to cause automatic closing of the gas valves.

After the gas has been shut off and the work stops rotating, provision is made for automatically ejecting the work and this brings in the element of the time of quenching. With some materials it is desirable to quench instantly, while with other materials a slight delay is' desired before the quenching takes place in order to obtain the best results. Means have been provided for making a selection between these two alternatives, and to this end a selector switch I44 is provided and this switch is directly connected to the power main I02. The operator sets this switch at the time he sets up the machine, and for 111- stantaneous quench he sets the switch on switch button I45. This establishes a circuit through relay !40, line I41, normally open timer relay contacts I 53 of a timer relay I40, and normally closed contacts 50 of work motor starter relay II 4.

The timer relay I40 is operated simultaneously with the motor controller relay II4 whereby the normally closed contacts I50 are opened and the timer relay contacts Hill are closed. The result is that the contacts I50 open before the contacts I48 close, so that the relay I46 does not become energized when the machine is started. The timer relay M9 is adjusted for a timed opening whereby when the relay contacts Ii'l open the contacts I50 close immediately but the contacts I40, being slow to open, complete a circuit to energize the relay I40. Energization of relay Hi6 closes contacts I'5I, thereby completing a circuit from power main I05 through ejector control relay I52, line I53 and closed contacts E5I to power main 02. When the relay 52 is energized it closes contacts 554 in a circuit from power main I05 to the ejector solenoid l0 and back to line I02. The work is thereby automatically ejected.

When a time delay is desired for ejection the selector switch 544 is placed on the contact button I55 thereby completing a circuit through line I56 to the timer relay contacts I51. The operation in this case is that the timer relay I58 is operated but being timed closed and instantaneous opened there will be a slight delay before the contacts I51 close and cause operation of relay I52 and thereby operation of the ejector.

Since the relay I52 is a timer relay it will automatically open after the ejection, thereby setting the circuit for the next cycle. It should also be noted that after the burners have been turned off that the movable indicator 98 of the temperature recording instrument 99 will recede, thereby reclosing switch IOI for the next cycle of operation.

It will thus be seen that when the work has reached the proper temperature that the machine is automatically shut down by closing off the gas supply, stopping rotation of the work spindle and ejecting the work for quenching either immediately or with a slight time delay.

If the machine is to be used in a conveyor line for high production work the modified form of machine shown in Figures 9 and 10 is utilized. In this machine when the work is ejected from the work supporting spindle I2 it falls onto a wire conveyor belt I59 which is traveling in the direction of the arrow I60. As shown in Figures 9 and 10 the belt I59 is mounted on, an idler pulley I6I which is rotatably supported on studs I62 mounted in and projecting from the opposite walls I 63 and I64 of the quenching tank. The sides of the belt are flanged as shown at 65 and these run in a first set of guide pulleys I66 located on the upper side of the belt and a second guide pulley I61 located near the bottom of the tank. The belt also runs over a driving drum I68 which is supported on a shaft I69 that is journaled in the opposite side walls of the tank in bearings I10 and H1.

The shaft I69 has a drive sprocket wheel I12 secured to one end thereof and connected by a drive chain I13 to a sprocket wheel I14 driven by the armature shaft I15 of gear reduction motor I16.

The motor I16, as shown in Figure 11, is connected in series with a start and stop switch I11 between lines I05 and I02. The switch I11 is composed of a pair of contacts forming part of a timer relay I18 which is connected in parallel with the ejection control relay I52 as shown in Figure 11. Therefore, each time the ejection relay I52 is operated to effect removal of a work piece the timer relay I18 is also energized which closes contacts I11 and causes operation of motor 516 causing movement of the conveyor belt I59 in the direction I60. After a predetermined interval of time the timer relay I18 will automatically release, thereby stopping the motor I16. It is thus obvious that the timer relay may be so set that the conveyor belt will travel a predetermined distance to remove the newly fallen work piece a predetermined distance up the incline I19 so that the next piece that falls into the tank will not hit or mar it. Eventually the work piece will move out of the quenching oil whereby the oil starts to drain from the work piece. To facilitate drying the work and removing the excess oil a blower pipe I is mounted in the upper part of the bed. This blower pipe is connected to a valve IBI The valve has an inlet I82 which may be connected to a source of compressed air supply represented by the numeral I83 and which supply is normally available in all plants today. The operating control lever I84 of the valve I8I is connected to a solenoid I85 which is also seril0 ally arranged in circuit with a pair of contacts I85 between lines I05 and I02 as shown in Figure 11. The contacts I86 are also part of the timer relay I18 whereby each time the relay is operated and the conveyor moved the blower will be turned on.

After the work reaches the top of the conveyor it is deposited on a slide I81 and may thereby be directed to a shop conveyor system represented generally by the reference numeral I88.

As shown in Figure 9 an incoming shop conveyor system, represented generally by the reference numeral H39, may be provided for depositing work on a work receiving shelf I90 attached to the front of the machine.

The operator thus has only to remove the work from the shelf I90, place it on the work receiving spindle I2 and push the start button I03 for each work piece.

It will be obvious that the entire machine may be shut down at any time by pressing the stop button I01.

For individual operation of the work driving motor relay H 5 a manually operable switch I9I is placed in series therewith as shown in Figure 11, but in order for this circuit to be effective it is necessary for the operator to press the start button I33 in order to close the relay I24. At this time the switch I08 will be placed in its manual position in contact With button I93.

' When the relay II l is operated in this way by manual operation it will close a pair of contacts I92 forming part of the relay and thereby latch itself in around the start button I9I whereby when the operator wants to stop the motor he actuates the stop button I26.

Similarly, if the operator wants to manually control the gas control relay I23 there is a manual control start button I94. This is connected in parallel with the contacts I30 of relay I23 whereby actuation with the manual control switch IM will close the latching-in contacts I30 and maintain the circuit so that in order to close the valves it is necessary for the operator to actuate the stop button I28. A neon light I95 is connected in circuit with the relay contacts I24 which is part of relay I04 so that whenever the start button IE3 is closed to establish a circuit to the temperature recording instrument a light I95 will be illuminated to indicate that the instrument is connected in the circuit. A second light IE9 is connected in series with the normally closed contacts 59 of the work motor control relay I I l whereby whenever this relay is operated to start rotation of the work the light I96 will go out.

Whenever the machine is shut down after completing the heat treating of a particular lot of work pieces with the machine under automatic control, it is desirable to remove whatever work pieces are still in the quenching tank and therefore a separate manual control switch I96 has been provided for the conveyor motor I16, as shown in Figure 11. One side of this switch is connected to the power main I05, and the other side of the switch is connected between the automatic control switch I11 and the motor I16. Thus, the manual control switch may be utilized at any time to effect operation of the conveyor motor at will.

It is desirable to prevent excessive heating of the parts, and therefore a water cooling system is provided comprising a control valve I91 to which is connected a suitable source of water supply I98. The valve I91 has branches I99 and 200 leading to the mixing chambers 49 and another branch 25! leading to the cooling tube 83 which surrounds the thermopile. The water returning from the mixing chamber is led through passages 252 and 203 to the torchheads 24 and 25, and after circulating through these heads passes to reservoir through the return pipes 204 and 205.

The compressed air supply represented by the reference numeral I83 may also be connected through the control valve 206 to the supply pipe '94 for supplying the viewing tube 8'1. A second valve 261 is provided for connecting the supply I83 to a pipe 208 which has a series of longitudinally spaced holes therein for creating a wall of circulating air in front of the column wall as shown in Figure 2 for reducing heat radiation from the torchheads against the front wall.

Attention is invited to the fact that only one spark gap I43 is shown for the torches, but it will be understood that a duplicate spark coil may be connected in parallel with the spark coil M6 or dependence may be placed upon one lighted torch lighting the escaping gas from the other torch.

In Figures 12 and 13 there is shown a modified form of burner which may be made in a form and size to suit a particular work piece. This burner provides or creates a more uniform heating zone because it is in a form of an almost continuous ring except for the opening for the heat radiation tube. This form of burner is economical where a long high production run of a particular size of work piece is being treated because it gives more uniform heating throughout the periphery of thework. This burner comprises a circular housing 299 from which radially extends from opposite sides a pair of supporting arms 2:9. These arms are of the same general shape and size of the supporting portions of the burners previously shown and are adapted to fit into the adjustable brackets 35 which were previously described. In this case the arms 2l0 are made hollow to form a receiving chamber 2 II to Which the gas inlet 48 is connected. The gas in this chamber passes through an opening 2I2 formed in the outer wall of the housing 209 and into an outer chamber 2i3 which extends all the Way around the housing 209. A bafile plate 2 ['4 is secured in the housing between end plates H5 and 215, thus dividing the interior of the housing 255 into an exterior chamber 2l3 and an interior chamber 2H. The baffle plate has a series of radial holes 2 I8 formed therein which serve to cause an even distribution and a more uniform pressure of the gas throughout the interior chamber 21?. A removable burner plate 219 is attached to the inside of the housing by a series of bolts 226, and this plate carries a series of radial holes 22l through which the gas passes and is ignited on the exterior surface thereof. The object of making the plate 215 removable is that other plates with various patterns and sizes of holes may be substituted to suit the various types of work being treated. By making the plate 2H3 of the proper material it is not necessary to use special burner tips.

It will be noted that the construction provides a pair of end chambers 222 and 223 through which water may be circulated to keep down the temperature. In order to maintain complete circulation the chamber 223, for instance, may have a water inlet connection at 224 and a water outlet connection-at 225 as shown in Figure 12 whereby the waterwill make a complete circuit around '12 and through one end of the housing. Similar connections may be provided for the other chamher 222.

It is well known that every time a combined mixture of oxygen and acetylene is ignited or extinguished, there is a minor explosion or at least a loud report. In a high production machine of the type disclosed herein this means a number of these explosions every minute because the gas must be extinguished and lighted for every work piece treated. Since such explosions are somewhat hazardous and also fatiguing to the operator, as well as disturbing to others around the vicinity of such a machine if placed in an open shop, means have been provided for minimizing such explosions to the extent of obtaining a quiet operating machine. This result is obtained b a timing control mechanism which causes the acetylene gas to flow'iirst to the burner and become ignited after which the oxygen gas is added. The opposite eifect is obtained when the gas is extinguishe'd--i. e., the oxygen gas is turned ofi first and then the acetylene gas is turned off.

This control mechanism is shown in Figure 14 of the drawings. From this figure it will be seen that separate solenoids have been provided for all of the valves. In other words, the oxygen supply line 59 terminates in a pair of valves 226 and 22? located in the valve blocks 2 28 and 229 respectively. The valves 226 and 2 21 correspond to the valve members 55in Figure 11. The acetylene supply line ti terminates in control valves 23:; and EH located in the respective valve blocks 228 and 229. The valves 225 and 221 are operated by solenoids 232 and 233, and these solenoids are connected in parallel to conductors 234 and 235, the conductor 234 being connected directly to the power main Hi5 and the conductor 235 being connected by a switch 236 to the power main I52. Similarl the valves 230 and 231 are operated by solenoids 23 i and 238 which are connected in parallel to conductors 235 and 240, the former being directly connected to power main 5'55 and the conductor 240 being connected by a switch 24! to the power main 32. There is reproduced in Figure 14 the switch l3l which is controlled from the gas control relay I23 and the "timer control relay l32 for the spark control which is the same as that shown in Figure 11. The relay I23 will no longer control the switch i2 3, but a new control mechanism is now provided for controlling the separate switches 236 and 24!. This new control mechanism is still timed for operation from the gas control relay 123 through its operation of the switch l3l. Thus, whenever the switch [3! is closed it completes a circuit through a timer relay 242 which is a timer control for delaying the flow of oxygen. At the same time the closing of switch l3| completes a circuit through a relay 243 which carries two sets of switch contacts 244 and 245. The contacts 2 .5 are normally closed, and the "contacts 244 are normally open. Thus, when the relay 2 3 is-operated, the contacts 245 open first and then the contacts 24-! close which completes a circuit through a relay 245, which relay carries the contacts 24% and thus closes a circuit to the solenoids 23? and 233 causing the acetyllene control valves 2-35 and 23l to open. This produces a flow of acetylene .gas to the burners. In the meantime the timer relay 242 which opcrates on the timed closing and instantaneous opening principle will subsequently cause a switch 247: to close, thereby completing a circuit to relay 248. The relay 248 carries the switch contacts 236 which will now close and. cause operation of the solenoids 232 and 233 for the oxygen control valves 226 and 221. Thus, it will be apparent that the acetylene valves will immediately open upon closing of the switch I3I and that the relay 248 will be momentarily delayed by the timer relay 242.

At the same time that the relay 248 was energized a second timer relay 249 connected in parallel therewith was energized and this relay carries the switch contacts 250. This relay operates on the principle of instantaneous closing and timed opening with the result that as soon as the relay 249 is energized the contacts 250 are closed, but since the switch contacts 245 are open no circuit connection is established to the relay 246.

When it is time to shut the gas off the switch I3! will open, causing deenergization of the timer relay 242 which, being set for instantaneous opening, will open the switch 241 and thereby deenergize the relay 248 which, in turn, will open the switch contacts 236 causing the oxygen control valves to immediately close. At the same time the relay 243 will be deenergized, opening switch 244 and closing switch 245. Since the switch 250 has a timed opening the circuit will be maintained through switch 259 and switch 245 to the relay 246 which controls the acetylene so that this relay will not be deenergized until the timed opening of switch 250 which will be subsequent to the closing of the oxygen control valves. Thus, the switch contacts 24! for the acetylene control valve solenoids will be delayed in opening until after the oxygen has been shut off. With this control arrangement the igniting and extinguishing of the burners may be carried out in a quiet manner.

There has thus been provided an improved heat treating machine which is capable of continuous automatic operation in which the only duty of the operator is to load the machine.

1. In a heat treating machine, the combination of a bed, a column upstanding from one side of the bed, a power rotatable spindle journaled in the column for rotating a work piece in spaced relation to the top of said bed, power operable means for firing a heat treating zone around the work carried by said spindle to heat the work to a predetermined temperature, a heating cycle starting and control circuit for said power operable means, means for energizing said circuit to cause said power operable means to initiate a heating cycle, power operable means for ejecting work from the spindle, temperature control means adjusted to respond to the heat of the work when equal to said predetermined temperature and operatively connected to deenergize said circuit and to efiect activation of said power operable ejecting means to eject work from said spindle, a quench tank located in the bed below said spindle containing a quenching medium for quenching the work, a power operable work conveying belt located in said medium for receiving the ejected work, and means responsive to each deenergization of said circuit to momentarily energize said last-named power operable means.

2. In a heat treating machine, the combination of a bed, a column upstanding from one side of the bed, a power rotatable spindle journaled in the column for rotating a work piece in spaced relation to the top of said bed, power operable means for firing a heat treating zone around the work carried by said spindle to heat the work to a predetermined temperature, a heating cycle starting and control circuit for said power opef able means, means for energizing said circuit to cause said power operable means to initiate a heating cycle, power operable means for ejecting work from the spindle, temperature control means adjusted to respond to the heat of the work when equal to said predetermined temperature and operatively connected to deenergize said circuit and to effect activation of said power operable ejecting means to eject work from said spindle, a quench tank located in the bed below said spindle containing a quenching medium for quenching the work, a power operable work conveying belt located in said medium for receiving the ejected work, and means responsive to each deenergization of said circuit to momentarily energize said last-named power operable means, said belt having an upwardly inclined portion for removing work from said medium, power operable means associated with said portion for emitting a blast of air on the passing work, and means responsive to each deenergization of said circuit to effect momentary energization of said lastnamed power operable means.

3. In an automatic machine for heat treating work to a predetermined temperature regardless or" time, the combination with power operable means for rotating a work piece, of power operable mearrs for creating and firing a heating zone around the work piece for heating the periphery thereof, a heating cycle starting and control circuit having a starting control relay operatively connected to said power operable means, switch means in said circuit for energizing said relay to effect automatic operation of said power operable means to start the heating cycle, a temperature control instrumentality having a presettable temperature indicator and a movable indicator, an electric thermopile mounted on the machine adjacent said zone for response to work heat radiation, said thermopile being electrically connected for actuation of said movable indicator for progressive movement thereof in accordance with increase in heat radiation on the thermopile, a normally closed switch in said circuit for maintaining energization thereof established by said switch means, said normally closed switch being adapted to be opened in response to juxtaposition of said indicators to break said circuit and stop the heating cycle.

4. In an automatic heat treating machine having a bed and, a column upstanding from the bed supporting a work receiving spindle, the combination of electrically operable means carried by the column for rotating said spindle, electrically operable means for firing a heating zone around said spindle, a heating cycle starting and control circuit including relays for energizing the respective electrically operable means, switch means for energizing said circuit to effect operation of said relays to start the heating cycle, electrically operable means for ejecting work from said spindle, a temperature control mechanism including a thermopile mounted adjacent said work support for response to direct heat radiation from the work, a movable indicator operatively connected to said thermopile for movement in response to increase in heat radiation from the work on the thermopile, a temperature selector indicator presettable in advance of said movable indicator to a predetermined temperature, a control switch in said circuit for maintaining energization thereof established by said switch means, said control switch being responsive to movement into juxtaposition of said indicators to deenergize said circuit to stop the heating cycle, a quench tank and timing means in said circuit responsive to deenergization thereof to efiect a timed energization of "said electrically opera'ble ejecting means to eject the work from said spindle into said quench tank, whereby the spindle may be loaded with another work piece during quenching of the heated work piece.

5. A flame hardening machine for automatically heating and quenching a work piece to a prescribed temperature comprising a work support, power operable means 'for firing a heating zone around the work support to effect heating of the work, a heating cycle starting and control circuit for said power operable means including switch meanslfor energizing said circuit to create automatically said heating zone, a temperature control mechanism for determining the temperature to which the work is to be heated and quenched including a temperature selector presettable to said prescribed temperature, a control switch in said circuit having a normal position for-maintaining energization'of said circuit established by said switch means, a thermopile positioned adjacent said work for instantaneous response to heat radiation from the work, means electrically connected to said thermopile for progressive movement in response to instantaneou's reactions on said electrical connections by said thermopile induced by increase in heat radi- 'ation on the thermopile and bein movable into juxtaposition with saidselector to effect operation of said "control switch to deenergize said power operable means to stop the heating cycle at said. prescribed temperature, a quenching medium, and means automatically responsive to deener- .gization of said circuit to eject the work from the work support into said quenching medium to effect immediate quenching of the work at said prescribed temperature.

6. In an automatic heat treating machine, the combination of a rotatable spindle, power operable'means for firing a heating zone around said spindle, additional power operable means for rotating said spindle, a heating cycle starting and control circuit for said power operable means including switch means for energizing said circuit to initiate operation of said power operable means, means presettable to the final temperature of the work including a control switch operatively 7 connected in said circuit to maintain energization thereof established by said switch means, a thermopile positioned adjacent said spindle for response to work heat radiation, work temperature indicating means including a movable element electrically connected to said thermopile for progressive movement in accordance with increase of heat radiation on said thermopile, said element being adapted to cause actuation of said control switch when moved into juxtaposition with the presettable means to deenergize said control 'circuit and thereby extinguish said heating zone and stop work rotation, and means responsive to deenergization of said control circuit to discharge work from said spindle.

7. In an automatic heat treating machine, the combination of a rotatable work spindle, power operable means for firing a heating zone around said spindle, a heating cycle starting and control circuit ror said power operable means including switch means for energizin said circuit to initiate operation of said power operable means, means presettable to the final temperature of the work including a control switch operatively connected in said circuit to maintain energization thereof established by said switch means, a thermopile position adjacent said spindle for response to work heat radiation, work temperature indicating means including a movable element electrically connected to said thermopile for progressive movement in accordance with increase in heat radiation on said thermopile, said element being adapted to cause actuation of said control switch when moved into juxtaposition with the presettable means to deenergize said control circuit, a quench tank located below the work spindle, and means responsive 'to deenergization of said circuit to automatically discharge work from said .spindle into said tank.

DAVID M. STRAUCHEN. MILTON GARVIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,152,848 Schliggemann Sept. 7, 1915 2,040,328 Olson May 12, 1936 2,085,856 Hunt et al July 6, 1937 2,215,576 Bucknam et al Sept. 24, 1940 12,220,002 Rollman et a1. Oct. 29, 1940 2,261,624 I nskeep Nov. 4, 1941 2,290,283 Jones July 21, 1942 2,322,305 McGuire June 22, 1943 2,354,656 Annesle vAug. 1, 1944 2,364,565 Stubbs Dec. 5, 1944 2,371,288 Frownfelter Mar. 13, 1945 2,394,002 Ness Feb. 5, 1946 2,-407,230 Furkert Sept. 10, 1946 2,410,005 Bishop et al Oct. 29, 1946 2,429,776 Shorter Oct. 28, 1947 12,455,447 Shorter Dec. 7, 1948 FOREIGN PATENTS Number Country Date 445,425 Great Britain Apr. 8, 1936 

